Optical instrument



oct. 13,1925- 1,557,328

H. C. REES OPTICAL I NSTRUMENT Filed Nov. 9, 1921 E @y www/ Patented Oct. 13, 1925.

UNITED STATESy HERBERT c. nEEs, or SAN ANToNro, Tis-jms..V

oPTIcAL INSTRUMENT.

. Application met November 9, V1921.- serial 1\ro..513,s75.`

To all whom t may concer Be it `known that I, HERBERT C. Runs, a citizen of Vthe United States, residingy at San Antonio, county of Bexar, and State of Texas, have invented a certain new and useful Improvement in Optical Instruments, of which the following is'a ull, clear, and exact. description, such as will enable others skilled in the art to which it appertains, to make and use the same, reference being had to the accompanying drawings, forming part of this application.

My invention relates to optical .instruments used for testing the accommodative convergence of the eye muscles and consists in a binocular phorometer in which the efficiency of the instrument is maintained uniformly by preserving a constant relation between the instrument and the eyes and the horizontal.

When the eyes are directed at an object, they accommodate and bring about an associated amountrof convergence, to an extent depending upon the distance of. the object viewed. Y

When the eyes are functioning under normal conditions, there is a constant com fortable enervation supplying both the accommodative and converging muscles, but this normal conditionwhich is termed orthophoria may be `effected by defective eyesight or other abnormal physiological conditions.

When the eyes are focused at the near point under non-orthophoric conditions,

they are subjected to strain and the main object of my invention is to provide a device which will test the accommodative convergence of the eyes and detect a non-orthophoric conditionan'd to practically indicate the extent thereof.

When the eyes are reading or doing other close work they normally lie in a horizontal plane. In testing the eyes, any departure from the horizontal of the same or of a chart with which they are being tested affects the value of the test and it is an object of my invention tov automatically secure horizontal positioning of the eyes and of all of the parts of the instrument. So far as I am aware, the securing of this result here- -tofore has been left to? the knowledge, skill and attention of the person employing the instrument. Y Inl the accompanying drawings, which illustrate a selected embodiment of my invention.-

Figurel is a side View of the device. Figure 2 is an end View looking towards the right.

Figure 3 is a vertical-transverse section on line 3-3 of Figure 1. i

Figure 4 is a vertical transverse section on the line 4 4 of Figure 1. f Tiltably mounted on the base 1 of my device is a longitudinal support "member 2 which I have shown as a cylindrical shell adjustable on the base by vmeans of a pin 3 and an adjusting screw 4. Suspended from pivotal mountings 5 andg onsupport 2 is a longitudinal element 7k extending substantially throughoutthe length of shell 2 and preferably made of a heavy material andin such form and size that the weight of the element will cause vsame to swing in shell 2 to a vertical position independently of the inclination of member 2 transversely of its longitudinal axis. Extending vupwardly -from each end of element 7 through suitable openings in shell 2l are holders 8 and 9, respectively. n

yI-Iolder 8 carries a plate l0.having openings 11 and a recess 12 which adapts the plate to be fitted to the human face.

Mounted on .plate 8 in front of openings 11 is a pair ofprisms 13 and 14, one of which is arranged with its `base up and the other with its base down; such a* prism arrange' ment being a common device for creating doublefimages. 'l

Holder 9 mounts a chart 15 which extends transversely of the longitudinal axis of member 2 and carries suitable indiciawhich vI have here shown as a red dot 16, a black arrow .17, anda horizontal blackline 18 below said arrow and dot, with a series of letters and numbers arranged along the line for the purpose ofenabling the patient to ,describe the relative position of the double images created by the prisms 13, and 14.

The degree of refraction of prisms 13 'and 14 is'snch that at the distance between same and chart`15 the departure of the retracted rays from eachother vertically will equal imageis `always in the fusion field of the top of the arrow in the lower image; this latter distance will not be so-'great as to suppress the desire for single vision which exists whenever the eyes view two similar objects near each other.

A phenomenon existing when a double image is created in front of the eyes in a manner similar to that described above, is. that the eyes will not align the ima-ges vertically but will oiiset them transversely. With four to six prism dioptres, adista'nce between prism and chart of forty (40) cm. and a dist-ance .between dot 16 and line 18 of forty-eight millimeters, the amount of vertical displacement with vnormaleyesight should equal the distance between .the dot and the line, and the above mentioned transverse Ioffset should be from tour .to six prism dioptres to the right. l(Physiologie exophoria.)

Upon viewing the chart through these lenses, if .the ire'd dot appears aboveor :below the line, there is a `condition of hyperplioria, and if the transverse location .of `the dot be `to the right :orvlett of the area indicated, there is a condition of yexophoria or eso*- lphoria, respectively. It any of these conditions exist, instead of the normal orthophoria, it is 'instantly indicated .and according to the departure of the dot, `as seen by the patient, from the proper area, the extent of thephysioflogical defect may be judged.

A level `19 disposed transversely of member 2 and mounted upon holder affords a convenient but .not essential means for indicating whether or .not the leveling feature of the instrument is functioning and also, 'by ftilting .the `chart vduring a test, for indicating .the degree of hy-,perphoria'.. l

. yIn the use of :a device 'ott the nature of the above :described instrument, :it may be set .upon a table, a stand, or maybe mounted upon la sii/inging 'bracket orotherwise supported, and in any-off these events, an accurate :leveling roi' the instrument is :unlikely to be obtained. This, however, will :be .iminaterialbecaiise of the self-leveling arrangement profvided by the suspended weight `element for the prisms and chart are rigidly united thereby..V The transverse line vof the .chart `and .the 'line intersecting the centers of openings ll will always be horizontal to 'the longitudinal :axis ofnieinmember on base l permits the prisms .and the-chart to .assume different heights.

Parallelism of plate .l0 and :chart '15 is also maintained although the inclination of the Lplatevand chart will vary with the .tilting jof imem-ber 2. Thistilting is "provided for :the purpose tif-adjusting the instrument to the height fof. the patient and also for obtaining "the downwardly inclined line of vision which normally exists in reading or working.

.By means of my instrument, .the eyes imay fmismas be tested when they are in a state of activity rather than when practically quiescent or relaxed as would be the case of the object viewed were some twenty feet away or at a still greater distance.

I contemplate the 'usual modifications in the details of my device, without departing from the spirit of the invention as set forth inthe following claims.

I claim:

l. In an optical instrument, a sighting del vice pivoted to swing transversely ioi' .its axis, a chart target rigidly associated therewith, and mea-ns ier. automatically .leveling said vdevice and target at right angles to .the axis lof the sighting device.

2. In an opticalinstrument, a sighting device adjustable in .the verticahplane of its axis and tiltablle'transversely of. it-s axis, a' .chart .target rigidly. associated therewith, .and means Vfor automatically leveling lsaid device and target at right anglesto the .axis ci the sighting device and independently of .its adjustment-in the 'ver-tical plane of its axis.

y3. In :optical instrument, a pair of prismsand acliart rigidly mounted in. relation to each other, .and .means for automatically leveling said prisms and chart.

4. An optical instrument comprising a longitudinal :support member, a 'pair of prisms-and a. chart nig-idly attached to said VJsupport member, and. mfeaiisftor automati Acally leveling said support member :at right angles to its axis.

5. Inranoptical instrument, asuppo-nt, a

"prism holder, a chart holder spaced `.there- `from, said holdersybeing pivotally mounted on sai-d support, and vmeans for automatically leveling fsaid fholders.

6. 'In .an .optical .'iistrument, .a support, a prism holder, a. .chart holder .spaced therefrom, said holders being pivotally mounted fon saidl support yand rigidly united, and

means for automatically leveling said hold ers.

7. `In optical instrument, a pair of prisms pivotally mounted, achart spaced from said prisms and pivotally mounted,

`and weight means .attached to said .prisms and chart tending to maintain same in .a

.predetermined relation to :the horizontal. ber l2, althoughthe pivotal mounting lof the V8. In an optical instrument, a longitudinal framea longitudinal member pivotally suspended from -said iframe, upwardly :ex-

tending elementsadjacentfto the ends of said uneinber., a pair of vision membersmounted yon the :upper portion of -one of .said lelernal casing, a longitudinal member in :said

casing pivotally suspended from` the top thereof, a `prism .andI a ychart mounted at spaced intervals on said member and held thereby so as to provide an uninterrupted line of vision between said prism and chart.

l0. In an optical instrument, a base, a longitudinal casing pivoted thereon to tilt in a vertical plane, a rigid element suspended from said casing carrying eye testing apparatus and adapted to maintain respective elements of said apparatus in predetermined relation to the horizontal independently of the inclination of said base and the tilting of said element.

11. In an instrument for testing the accommodative convergence of the eyes, a pair oi' lenses, a chart target, meansfor inclining the lenses and target to provide normal reading position of the eyes being tested, and means for automatically maintaining the target in predetermined relation to the horizontal independently of the inclination of the lenses and said first mentioned means.

12. An instrument for determining the accommodation of the eye muscles by measuring the convergence of the eyes under normal working conditions, comprising a prism arrangement for producing double images, and a chart to be viewed therethrough to measure any departure from the normal in the relative positions of said images, and means for automatically leveling said prism arrangement and chart.-

13. An instrument for determining the accommodation of the eye muscles by measuring the convergence of the eyes under normal working conditions, comprising a prism arrangement for producing double images, and a chart to be viewed through said arrangement, means for tilting the instrument longitudinally of the line of vision, and means for automatically leveling the instrument transversely of the line of vision.

14. An instrument for indicating a nonorthopho-ric state of the eyes including a pair of prisms for producing double images under normal reading conditions of the eyes and a chart in rigid relation therewith for indicating the relation of said images to each other, and automatic leveling means for said prisms and chart.

15. An optical instrument for determining excessive or insuificient accommodative convergence effort at the near point, comprising means for creating double images without suppressing the desire for single vision, and means for simultaneously indicating the distance between the double images and their direction from each other.

16. A device for determining non-orthophoric conditions comprising a pair of prisms, arranged base up and base down respectively, and a chart arranged before said prisms bearing a horizontal line and t dot of a different color spaced above said ine.

17. A device for determining non-orthophoric conditions -comprising a pair of prisms, arranged base up and base down respectively, a chart arranged in front of said prisms, a horizontal divided line on said chart, a dot on said chart spaced above said line, the refractive index of said prisms and the distance between them and said chart being such that with normal eyesight, one image of said dot prduced by said prisms will be superimposed on said line at a predetermined point thereon.

In testimony whereof I hereunto affix my signature this 3rd day of November, 1921.

HERBERT C. BEES. 

